In a cellular radio network, the size of cells may vary according to the predicted capacity requirement of an area, for instance. In a sparsely populated area, the cells often are large macro cells, whereas in population centres, the reuse of frequencies must be more efficient, which aim is reached by reducing the size of cells, i.e. by using micro or pico cells. The diameter of a pico cell is typically at most a few dozen meters, and its transmission power level is at most a few hundred milliwatts; the diameter of a micro cell is at most a few hundred meters, and its transmission power level at most a few watts, and the diameter of a macro cell is at most a few dozen kilometers, and its transmission power level at most a few dozen watts. Macro cells are typically used to cover large areas, a micro cell covers a multi-storey office building and its vicinity, for instance, and a pico cell covers an area of a few offices inside a building, for instance. The size hierarchy of cells can also have several levels, and the definitions of the names may vary, but the essential thing is that cells of various sizes can be placed on top of each other, if necessary.
It is difficult to configure physical channels of at least partly geographically overlapping cellular radio networks using various cell sizes, if for capacity reasons, the same channel area needs to be divided between various cellular radio networks. A situation where a cellular radio network comprising micro and/or pico cells and using the same channel area operates in the service area of a cellular radio network comprising macro cells and operating in a population centre, can be given as an example. In such a case, the channel configuration of the micro/pico cell radio network can be implemented using fixed channel allocation and the same channel space with the macro cell radio network, whereby the operation of the micro/pico cell radio network must be ensured by a careful channel planning so that the macro cell radio network which has a higher transmission power level does not cause too much interference.
Especially, when the channel allocation of the macro cell radio network changes, the operation of the micro/pico cell radio network must be ensured by a fast channel planning, channel configuration and operational testing. Today, the operation is checked by measurements performed manually by measurement personnel in the cells. This testing is slow and expensive, especially at night time or in regularly repeated measurements.